Traditionally, it was thought that taking Calcium supplements could only slow bone loss.  Recent research suggests otherwise.  It appears that the form of the calcium matters, and most likely the status of vitamins D3 and K2.  Below are two studies reflecting the use of Algaecal brand plant calcium.  The first study showed an increase in bone density over a 1-year time frame.  The second study was a 7-year study showing yearly increase in bone density, and importantly no increase in cardiovascular risk.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3053489/

https://pubmed.ncbi.nlm.nih.gov/26885697/

At Complete Health, we carry Algaecal as Osteo Vegan by Numedica.